Methods and apparatus for collaborative partition coding for region based filters

ABSTRACT

Methods and apparatus are provided for collaborative partition coding for region based filters. An apparatus includes a video encoder ( 100 ) for encoding image data for a plurality of regions in a picture. The video encoder ( 100 ) includes multiple filters for filtering the image data based on region partition information for the plurality of regions. The region partition information for the plurality of regions is shared between the multiple filters.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/223,523, filed Jul. 7, 2009, which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD

The present principles relate generally to video encoding and decodingand, more particularly, to methods and apparatus for collaborativepartition coding for region based filters.

BACKGROUND

In recent years, region based in-loop and out-loop filters, such asinterpolation filters, de-blocking/de-artifacting filters, pre/postprocessing filters, loop filters, and so forth, are emerging in videocoding to improve coding efficiency and perceptual quality. Such filtersusually partition a video frame into multiple regions based on contentor rate-distortion (RD) cost. Then the filter structure and/orparameters can adapt to the local content characteristics of eachregion. This approach works well for non-stationary video signals.However, the region based filter usually has to spend overhead bits tocode the partitions/segmentations, which would degrade the overallperformance brought by the adaptation. This is especially true whenmultiple region based filters exist at the same time in anencoder/decoder, and the segmentation is independently done for eachfilter. The bits paid for coding the segmentations of all filters wouldbe demanding and can take away the gain obtained from these filters.

Block Adaptive Loop Filter (BALF)

In a first prior art approach, a block based adaptive loop filter isproposed, wherein a reconstructed frame is restored towards the originalframe by a Wiener filter. The coefficients of the Wiener filter areestimated at the encoder and sent to the decoder as side information.Although a Wiener filter can restore the reconstructed frame to theoriginal frame globally, there are degraded pixels locally. Since thedegraded areas reduce the predictive efficiency for future codingframes, not filtering these areas will improve the coding performance.In BALF, the frame is partitioned into equal-size blocks, and a switchflag is used for each block to control whether or not the block isfiltered. In a second prior art approach, a quad-tree scheme isintroduced to indicate whether or not a variable-size block of a frameis filtered. When using the variable-size block scheme, the overhead forcoding the sizes and locations of blocks is demanding although thefilter performance is better than the equal-size block scheme.

Spatio-Temporal Adaptive Loop Filter (STALF)

Inspired by sparsity-based de-noising techniques, a nonlinear in-loopfilter has been proposed in a third prior art approach. The nonlinearin-loop filter averages multiple de-noised estimates which are obtainedby thresholding the coefficients in an over-complete transform domain.For de-artifacting work, the choice of filtering parameters such as, forexample, threshold, is important. The applied threshold plays a crucialpart in controlling the de-noising capacity of the filter as well as incomputing the averaging weights used in emphasizing the betterde-noising estimates. In the third prior art approach, thresholds thatare selected per pixel class based on quantization parameter (QP) andcoding mode information are encoded and transmitted as side informationto the decoder. The threshold does not adapt based on the video content.

A block based filter parameter adaptation scheme has also been proposedfor use in improving the performance of the above sparsity basedde-artifacting filter in video compression. More specifically, theadaptation of the filter parameters is based, not only on thequantization parameter and coding information, but also on the regionsof the video sequences, which achieves the spatio-temporal adaptation.In each region, the filter parameters (e.g., threshold) are selectedbased on a rate-distortion cost, since the region information and theparameters need to be signaled.

Multiple Region Based Filters

When there is more than one region based filter existing in anencoder/decoder, the partition or segmentation of a frame is performedindependently for each filter. The partition information also needs tobe sent to the decoder for each filter, which is redundant because thesegmentation usually has a strong correlation to the video content.

SUMMARY

These and other drawbacks and disadvantages of the prior art areaddressed by the present principles, which are directed to methods andapparatus for collaborative partition coding for region based filters.

According to an aspect of the present principles, there is provided anapparatus. The apparatus includes a video encoder for encoding imagedata for a plurality of regions in a picture. The video encoder includesmultiple filters for filtering the image data based on region partitioninformation for the plurality of regions. The region partitioninformation for the plurality of regions is shared between the multiplefilters.

According to another aspect of the present principles, there is provideda method in a video encoder. The method includes encoding image data fora plurality of regions in a picture. The image data is filtered bymultiple filters based on region partition information for the pluralityof regions. The region partition information for the plurality ofregions is shared between the multiple filters.

According to yet another aspect of the present principles, there isprovided an apparatus. The apparatus includes a video decoder fordecoding image data for a plurality of regions in a picture. The videodecoder includes multiple filters for filtering the image data based onregion partition information for the plurality of regions. The regionpartition information for the plurality of regions is shared between themultiple filters.

According to a further aspect of the present principles, there isprovided a method in a video decoder. The method includes decoding imagedata for a plurality of regions in a picture. The image data is filteredby multiple filters based on region partition information for theplurality of regions. The region partition information for the pluralityof regions is shared between the multiple filters.

These and other aspects, features and advantages of the presentprinciples will become apparent from the following detailed descriptionof exemplary embodiments, which is to be read in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present principles may be better understood in accordance with thefollowing exemplary figures, in which:

FIG. 1 is a block diagram for an exemplary video encoder to which thepresent principles may be applied in accordance with an embodiment ofthe present principles;

FIG. 2 is a block diagram for an exemplary video decoder to which thepresent principles may be applied in accordance with an embodiment ofthe present principles;

FIG. 3 is a flow diagram for an exemplary method for encoding picturedata using collaborative partition coding for region based filters inaccordance with an embodiment of the present principles;

FIG. 4 is a flow diagram for an exemplary method for decoding picturedata using collaborative partition coding for region based filters inaccordance with an embodiment of the present principles;

FIG. 5 is a flow diagram for another exemplary method for encodingpicture data using collaborative partition coding for region basedfilters in accordance with an embodiment of the present principles;

FIG. 6 is a flow diagram for another exemplary method for decodingpicture data using collaborative partition coding for region basedfilters in accordance with an embodiment of the present principles;

FIG. 7 is a flow diagram for yet another exemplary method for encodingpicture data using collaborative partition coding for region basedfilters in accordance with an embodiment of the present principles; and

FIG. 8 is a flow diagram for yet another exemplary method for decodingpicture data using collaborative partition coding for region basedfilters in accordance with an embodiment of the present principles.

DETAILED DESCRIPTION

The present principles are directed to methods and apparatus forcollaborative partition coding for region based filters.

The present description illustrates the present principles. It will thusbe appreciated that those skilled in the art will be able to devisevarious arrangements that, although not explicitly described or shownherein, embody the present principles and are included within its spiritand scope.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the presentprinciples and the concepts contributed by the inventor(s) to furtheringthe art, and are to be construed as being without limitation to suchspecifically recited examples and conditions.

Moreover, all statements herein reciting principles, aspects, andembodiments of the present principles, as well as specific examplesthereof, are intended to encompass both structural and functionalequivalents thereof. Additionally, it is intended that such equivalentsinclude both currently known equivalents as well as equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the artthat the block diagrams presented herein represent conceptual views ofillustrative circuitry embodying the present principles. Similarly, itwill be appreciated that any flow charts, flow diagrams, statetransition diagrams, pseudocode, and the like represent variousprocesses which may be substantially represented in computer readablemedia and so executed by a computer or processor, whether or not suchcomputer or processor is explicitly shown.

The functions of the various elements shown in the figures may beprovided through the use of dedicated hardware as well as hardwarecapable of executing software in association with appropriate software.When provided by a processor, the functions may be provided by a singlededicated processor, by a single shared processor, or by a plurality ofindividual processors, some of which may be shared. Moreover, explicituse of the term “processor” or “controller” should not be construed torefer exclusively to hardware capable of executing software, and mayimplicitly include, without limitation, digital signal processor (“DSP”)hardware, read-only memory (“ROM”) for storing software, random accessmemory (“RAM”), and non-volatile storage.

Other hardware, conventional and/or custom, may also be included.Similarly, any switches shown in the figures are conceptual only. Theirfunction may be carried out through the operation of program logic,through dedicated logic, through the interaction of program control anddedicated logic, or even manually, the particular technique beingselectable by the implementer as more specifically understood from thecontext.

In the claims hereof, any element expressed as a means for performing aspecified function is intended to encompass any way of performing thatfunction including, for example, a) a combination of circuit elementsthat performs that function or b) software in any form, including,therefore, firmware, microcode or the like, combined with appropriatecircuitry for executing that software to perform the function. Thepresent principles as defined by such claims reside in the fact that thefunctionalities provided by the various recited means are combined andbrought together in the manner which the claims call for. It is thusregarded that any means that can provide those functionalities areequivalent to those shown herein.

Reference in the specification to “one embodiment” or “an embodiment” ofthe present principles, as well as other variations thereof, means thata particular feature, structure, characteristic, and so forth describedin connection with the embodiment is included in at least one embodimentof the present principles. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment”, as well any other variations,appearing in various places throughout the specification are notnecessarily all referring to the same embodiment.

It is to be appreciated that the use of any of the following “/”,“and/or”, and “at least one of”, for example, in the cases of “NB”, “Aand/or B” and “at least one of A and B”, is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of both options (A andB). As a further example, in the cases of “A, B, and/or C” and “at leastone of A, B, and C”, such phrasing is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of the third listedoption (C) only, or the selection of the first and the second listedoptions (A and B) only, or the selection of the first and third listedoptions (A and C) only, or the selection of the second and third listedoptions (B and C) only, or the selection of all three options (A and Band C). This may be extended, as readily apparent by one of ordinaryskill in this and related arts, for as many items listed.

Moreover, as used herein, the words “picture” and “image” are usedinterchangeably and refer to a still image or a picture from a videosequence. As is known, a picture may be a frame or a field.

Further, as used herein, the phrase “picture region” (or simply “region”for short) refers to a portion of a picture encompassing and/orotherwise formulated from, for example, one or more blocks or arbitraryshapes of any size. The one or more blocks may relate to, for example, asuper macroblock, a macroblock, a macroblock partition, a sub-macroblockpartition, and so forth.

Additionally, as used herein, the phrase “region partition information”refers to how the picture is partitioned into picture regions. Thus,such region partition information may include, but is not limited to,for example, the block size if the picture is partitioned into equallysized non-overlapped blocks, or object edges if the picture ispartitioned based on an object.

Moreover, as used herein, the word “signal” refers to indicatingsomething to a corresponding decoder. For example, the encoder maysignal region partition information and/or filter parameters in order tomake the decoder aware of which region partition information and filterparameters were used on the encoder side. In this way, the same regionpartition information and filter parameters may be used at both theencoder side and the decoder side. Thus, for example, an encoder maytransmit a particular set of region partition information and filterparameters to the decoder so that the decoder may use the sameparticular set of region partition information and filter parameters or,if the decoder already has the particular region partition informationand filter parameters as well as others, then signaling may be used(without transmitting) to simply allow the decoder to know and selectthe particular set of region partition information and filterparameters. By avoiding transmission of any actual region partitioninformation and filter parameters, a bit savings may be realized. It isto be appreciated that signaling may be accomplished in a variety ofways. For example, one or more syntax elements, flags, and so forth maybe used to signal information to a corresponding decoder.

Further, as used herein, “high level syntax” refers to syntax present inthe bitstream that resides hierarchically above the macroblock layer.For example, high level syntax, as used herein, may refer to, but is notlimited to, syntax at the slice header level, Supplemental EnhancementInformation (SEI) level, Picture Parameter Set (PPS) level, SequenceParameter Set (SPS) level and Network Abstraction Layer (NAL) unitheader level.

Also, it is to be appreciated that while one or more examples of thepresent principles described herein may be so described with respect totwo in-loop filters (Filter1 and Filter2) exploiting the sharedsegmentation information, the present principles are not limited to thesame and, thus, other numbers of filters may also be used in accordancewith the teachings of the present principles provided herein, whilemaintaining the spirit and scope of the present principles.

Turning to FIG. 1, a video encoder to which the present principles maybe applied is indicated generally by the reference numeral 100.

The video encoder 100 includes a frame ordering buffer 110 having anoutput in signal communication with a non-inverting input of a combiner185. An output of the combiner 185 is connected in signal communicationwith a first input of a transformer and quantizer 125. An output of thetransformer and quantizer 125 is connected in signal communication witha first input of an entropy coder 145 and a first input of an inversetransformer and inverse quantizer 150. An output of the entropy coder145 is connected in signal communication with a first non-invertinginput of a combiner 190. An output of the combiner 190 is connected insignal communication with a first input of an output buffer 135.

A first output of an encoder controller 105 is connected in signalcommunication with a second input of the frame ordering buffer 110, asecond input of the inverse transformer and inverse quantizer 150, aninput of a picture-type decision module 115, a first input of amacroblock-type (MB-type) decision module 120, a second input of anintra prediction module 160, a second input of a partition optimizer165, a first input of a motion compensator 170, a first input of amotion estimator 175, and a second input of a reference picture buffer180.

A second output of the encoder controller 105 is connected in signalcommunication with a first input of a Supplemental EnhancementInformation (SEI) inserter 130, a second input of the transformer andquantizer 125, a second input of the entropy coder 145, a second inputof the output buffer 135, and an input of the Sequence Parameter Set(SPS) and Picture Parameter Set (PPS) inserter 140.

An output of the SEI inserter 130 is connected in signal communicationwith a second non-inverting input of the combiner 190.

A first output of the picture-type decision module 115 is connected insignal communication with a third input of the frame ordering buffer110. A second output of the picture-type decision module 115 isconnected in signal communication with a second input of amacroblock-type decision module 120.

An output of the Sequence Parameter Set (SPS) and Picture Parameter Set(PPS) inserter 140 is connected in signal communication with a thirdnon-inverting input of the combiner 190.

An output of the inverse quantizer and inverse transformer 150 isconnected in signal communication with a first non-inverting input of acombiner 119. An output of the combiner 119 is connected in signalcommunication with a first input of the intra prediction module 160 anda first input of the partition optimizer 165. An output of the partitionoptimizer 165 is connected in signal communication with an input of afilter-1 166. An output of the filter-1 166 is connected in signalcommunication with an input of a filter-2 167. An output of the filter-2167 is connected in signal communication with a first input of areference picture buffer 180. An output of the reference picture buffer180 is connected in signal communication with a second input of themotion estimator 175 and a third input of the motion compensator 170. Afirst output of the motion estimator 175 is connected in signalcommunication with a second input of the motion compensator 170. Asecond output of the motion estimator 175 is connected in signalcommunication with a third input of the entropy coder 145.

An output of the motion compensator 170 is connected in signalcommunication with a first input of a switch 197. An output of the intraprediction module 160 is connected in signal communication with a secondinput of the switch 197. An output of the macroblock-type decisionmodule 120 is connected in signal communication with a third input ofthe switch 197. The third input of the switch 197 determines whether ornot the “data” input of the switch (as compared to the control input,i.e., the third input) is to be provided by the motion compensator 170or the intra prediction module 160. The output of the switch 197 isconnected in signal communication with a second non-inverting input ofthe combiner 119 and an inverting input of the combiner 185.

A first input of the frame ordering buffer 110 and an input of theencoder controller 105 are available as inputs of the encoder 100, forreceiving an input picture 101. Moreover, a second input of theSupplemental Enhancement Information (SEI) inserter 130 is available asan input of the encoder 100, for receiving metadata. An output of theoutput buffer 135 is available as an output of the encoder 100, foroutputting a bitstream.

Turning to FIG. 2, a video decoder to which the present principles maybe applied is indicated generally by the reference numeral 200.

The video decoder 200 includes an input buffer 210 having an outputconnected in signal communication with a first input of an entropydecoder 245. A first output of the entropy decoder 245 is connected insignal communication with a first input of an inverse transformer andinverse quantizer 250. An output of the inverse transformer and inversequantizer 250 is connected in signal communication with a secondnon-inverting input of a combiner 225. An output of the combiner 225 isconnected in signal communication with a second input of a partitiongenerator 265 and a first input of an intra prediction module 260. Asecond output of the partition generator 265 is connected in signalcommunication with a first input of a filter-1 266. An output of thefilter-1 266 is connected in signal communication with a first input ofa filter-2 267. An output of the filter-2 267 is connected in signalcommunication with a first input of a reference picture buffer 280. Anoutput of the reference picture buffer 280 is connected in signalcommunication with a second input of a motion compensator 270.

A second output of the entropy decoder 245 is connected in signalcommunication with a third input of the motion compensator 270, a firstinput of the deblocking filter 265, and a third input of the intrapredictor 260. A third output of the entropy decoder 245 is connected insignal communication with an input of a decoder controller 205. A firstoutput of the decoder controller 205 is connected in signalcommunication with a second input of the entropy decoder 245. A secondoutput of the decoder controller 205 is connected in signalcommunication with a second input of the inverse transformer and inversequantizer 250. A third output of the decoder controller 205 is connectedin signal communication with a third input of the deblocking filter 265,a second input of the filter-1 266, and a second input of the filter-2267. A fourth output of the decoder controller 205 is connected insignal communication with a second input of the intra prediction module260, a first input of the motion compensator 270, and a second input ofthe reference picture buffer 280.

An output of the motion compensator 270 is connected in signalcommunication with a first input of a switch 297. An output of the intraprediction module 260 is connected in signal communication with a secondinput of the switch 297. An output of the switch 297 is connected insignal communication with a first non-inverting input of the combiner225.

An input of the input buffer 210 is available as an input of the decoder200, for receiving an input bitstream. A first output of the deblockingfilter 265 is available as an output of the decoder 200, for outputtingan output picture.

As noted above, the present principles are directed to methods andapparatus for collaborative partition coding for region based filters.We observe there are a lot of consistency between segmentation resultsfrom various region based filters, since they are based on either videoencoding information, like coding modes, or video content itself.Motivated by this observation and knowledge, we propose a collaborativecoding approach for the partition/segmentation information of regionbased filters, in order to further improve the coding efficiency.

Thus, in accordance with one or more embodiments of the presentprinciples, methods and apparatus are provided for collaborativelycoding the partition information for multiple region based filterswithin an encoder/decoder. Since most of the region in-loop or out-loopfilters want to adapt to the video content statistics, their partitionsor segmentations based on the video content statistics should havecorrelations. In this way, the partition information of one filter canbe shared with other filters to avoid spending more overhead bits.

In one embodiment, the partition/segmentation can be done and optimizedjointly based on picture rate-distortion (RD) cost. Thus, the outputpartition/segmentation is optimal in the RD sense and can be used by allthe filters joining the optimization. In each partition of a picture,different filters can set different filtering parameters for thatregion, which realizes the adaptation. In another embodiment, thesegmentation/partition information is decided by jointly consideringparameter adaptation based on coding information, picture content, andso forth.

In another embodiment, the partition can be performed and optimized forone filter. Then the output partition of this filter can be used forsome other filters. This scheme can decrease the complexity inpartition/segmentation optimization, but can also probably degrade thefiltering performance.

In another embodiment, some of the filters can share the same regionsegmentation/partition information while other filters use their ownsegmentation/partition.

The region segmentation/partition information can be signaled using, forexample, a high level syntax or a region level syntax. Alternatively,the region segmentation/partition information can be inferred fromprevious coded regions/pictures/sequences.

Syntax

TABLE 1 shows exemplary slice header syntax elements in accordance withan embodiment of the present principles.

TABLE 1 slice_header( ) { Descriptor  ...  share_partition_flag u(1)  If(share_partition_flag==1){    shared_filter_seg_info u(v)  }  else  {  For (i=0; i<num_of_filters; i++){    filter_seg_info[i] u(v)   }  }  ... }

Semantics of some of the syntax elements of TABLE 1 are as follows:

share_partition_flag equal to 1 specifies that a collaborative partitionapproach is used for the slice. share_partition_flag equal to 0specifies that a collaborative partition approach is not used which, inturn, means that each filter will use its own partitions.shared_filter_seg_info specifies the filter segmentation informationthat is shared among multiple filters.filter_seg_info[i] specifies the filter segmentation information of thei^(th) filter if it does not use the shared segmentation information.

Turning to FIG. 3, an exemplary method for encoding picture data usingcollaborative partition coding for region based filters is indicatedgenerally by the reference numeral 300. The method 300 includes a startblock 305 that passes control to a loop limit block 310. The loop limitblock 310 begins a loop over (different available) segmentationapproaches, and passes control to a loop limit block 315. The loop limitblock 315 begins a loop over each (available) partition by the (current)segmentation approach, and passes control to a loop limit block 320. Theloop limit block 320 loops over the filter parameter set, and passescontrol to a function block 325. The function block 325 performsfiltering using a first filter (filter-1), and passes control to afunction block 330. The function block 330 performs filtering using asecond filter (filter-2), and passes control to a loop limit block 335.The loop limit block 335 ends the loop over the filter parameter set,and passes control to a function block 340. The function block 340 setsthe best filter parameters for this partition (e.g., based on arate-distortion cost and/or some other criteria), and passes control toa loop limit block 345. The loop limit block 345 ends the loop over eachpartition by the segmentation approach, and passes control to a looplimit block 350. The loop limit block 350 ends the loop over thesegmentation approaches, and passes control to a function block 355. Thefunction block 355 sets the best segmentation (e.g., based on arate-distortion cost and/or some other criteria), and passes control toa function block 360. The function block 360 encodes the sharedsegmentation, and passes control to a function block 365. The functionblock 365 encodes the filter parameters for the partition, and passescontrol to an end block 399.

Turning to FIG. 4, an exemplary method for decoding picture data usingcollaborative partition coding for region based filters is indicatedgenerally by the reference numeral 400. The method 400 includes a startblock 405 that passes control to a function block 410. The functionblock 410 parses the current segmentation, and passes control to afunction block 415. The function block 415 parses the filter parametersfor each partition, and passes control to a loop limit block 420. Theloop limit block 420 begins a loop over each partition, and passescontrol to a function block 425. The function block 425 sets the filterparameters, and passes control to a function block 430. The functionblock 430 performs filtering using filter-1, and passes control to afunction block 435. The function block 435 performs filtering usingfilter-2, and passes control to a loop limit block 440. The loop limitblock 440 ends the loop over each partition, and passes control to anend block 499.

Turning to FIG. 5, another exemplary method for encoding picture datausing collaborative partition coding for region based filters isindicated generally by the reference numeral 500. The method 500includes a start block 505 that passes control to a loop limit block510. The loop limit block 510 begins a loop over (different available)segmentation approaches, and passes control to a loop limit block 515.The loop limit block 515 begins a loop over each (available) partitionby the (current) segmentation approach, and passes control to a looplimit block 520. The loop limit block 520 begins a loop over a filterparameter set, and passes control to a function block 525. The functionblock 525 performs filtering using filter-1, and passes control to aloop limit block 535. The loop limit block 535 ends the loop over thefilter parameter set, and passes control to a function block 540. Thefunction block 540 sets the best filter parameters for this partition(e.g., based on a rate-distortion cost and/or some other criteria), andpasses control to a loop limit block 545. The loop limit block 545 endsthe loop over each partition by the segmentation approach, and passescontrol to a loop limit block 550. The loop limit block 550 ends theloop over the segmentation approaches, and passes control to a functionblock 555. The function block 555 sets the best segmentation (e.g.,based on a rate-distortion cost and/or some other criteria), and passescontrol to a function block 560. The function block 560 encodes theshared segmentation, and passes control to a function block 562. Thefunction block 562 finds the best filter parameters for filter-2 withthe shared segmentation, and passes control to a function block 565. Thefunction block 565 encodes the filter parameters for filter-1 andfilter-2, and passes control to an end block 599.

Turning to FIG. 6, another exemplary method for decoding picture datausing collaborative partition coding for region based filters isindicated generally by the reference numeral 600. The method 600includes a start block 605 that passes control to a function block 610.The function block 610 parses a segmentation, and passes control to afunction block 615. The function block 615 parses filter parameters foreach partition for filter-1 and filter-2, and passes control to a looplimit block 620. The loop limit block 620 begins a loop over eachpartition, and passes control to a function block 625. The functionblock 625 sets the filter parameters, and passes control to a functionblock 630. The function block 630 performs filtering using filter-1, andpasses control to a function block 635. The function block 635 performsfiltering using filter-2, and passes control to a loop limit block 640.The loop limit block 640 ends the loop over each partition, and passescontrol to an end block 699.

Turning to FIG. 7, yet another exemplary method for encoding picturedata using collaborative partition coding for region based filters isindicated generally by the reference numeral 700. The method 700includes a start block 705 that passes control to a loop limit block710. The loop limit block 710 begins a loop over (available)segmentation approaches, and passes control to a loop limit block 715.The loop limit block 715 begins a loop over each partition by the(current) segmentation approach, and passes control to a loop limitblock 720. The loop limit block 720 begins a loop over a filterparameter set, and passes control to a function block 725. The functionblock 725 performs filtering using filter-1, and passes control to afunction block 730. The function block 730 performs filtering usingfilter-2, and passes control to a loop limit block 735. The loop limitblock 735 ends the loop over the filter parameter set, and passescontrol to a function block 740. The function block 740 sets the bestfilter parameters for this partition (e.g., based on a rate-distortioncost and/or some other criteria), and passes control to a loop limitblock 745. The loop limit block 745 ends the loop over each partition bythe segmentation approach, and passes control to a loop limit block 750.The loop limit block 750 ends the loop over the segmentation approaches,and passes control to a function block 755. The function block 755 setsthe best segmentation (e.g., based on a rate-distortion cost and/or someother criteria), and passes control to a function block 758. Thefunction block 758 finds the best filter parameters and segmentation forfilter-3, and passes control to a function block 760. The function block760 encodes the shared segmentation and (any non-shared) segmentationfor filter-3, and passes control to a function block 765. The functionblock 765 encodes filter parameters for filter-1, filter-2, andfilter-3, and passes control to an end block 799.

Turning to FIG. 8, yet another exemplary method for decoding picturedata using collaborative partition coding for region based filters isindicated generally by the reference numeral 800. The method 800includes a start block 805 that passes control to a function block 810.The function block 810 parses the shared segmentation and (non-shared)segmentation for filter-3, and passes control to a function block 815.The function block 815 parses filter parameters for each partition forfilter-1, filter-2, and filter-3, and passes control to a loop limitblock 820. The loop limit block 820 begins a loop over each partition,and passes control to a function block 825. The function block 825 setsfilter parameters, and passes control to a function block 830. Thefunction block 830 performs filtering using filter-1, and passes controlto a function block 835. The function block 835 performs filtering usingfilter-2, and passes control to a loop limit block 838. The loop limitblock 838 ends the loop over each partition, and passes control to afunction block 840. The function block 840 applies filter-3 and itssegmentation and filter parameters, and passes control to an end block899.

A description will now be given of some of the many attendantadvantages/features of the present invention, some of which have beenmentioned above. For example, one advantage/feature is an apparatushaving a video encoder for encoding image data for a plurality ofregions in a picture. The video encoder includes multiple filters forfiltering the image data based on region partition information for theplurality of regions. The region partition information for the pluralityof regions is shared between the multiple filters.

Another advantage/feature is the apparatus having the video encoder asdescribed above, wherein the region partition information is combinedwith filter parameter adaptation based on at least one of codinginformation and picture content.

Yet another advantage/feature is the apparatus having the video encoderas described above, wherein at least one of the region partitioninformation and filter parameters for the multiple filters are signaledusing one or more high level syntax elements or one or more region levelsyntax elements, or are inferred by a corresponding decoder from atleast one of previously coded regions, previously coded pictures, andpreviously coded video sequences, the picture corresponding to acurrently coded video sequence.

Still another advantage/feature is the apparatus having the videoencoder as described above, wherein the multiple filters include atleast one of at least one in-loop filter, at least one out-loop filter,at least one pre-processing filter, and at least one post-processingfilter.

Moreover, another advantage/feature is the apparatus having the videoencoder as described above, wherein a partitioning of the picture intothe plurality of regions, from which the region partitioning informationis based, is jointly optimized by the multiple filters.

Further, another advantage/feature is the apparatus having the videoencoder as described above, wherein a partitioning of the picture intothe plurality of regions, from which the region partitioning informationis based, is optimized by one of the multiple filters, and is sharedwith other ones of the multiple filters.

Also, another advantage/feature is the apparatus having the videoencoder as described above, wherein the region partition information forthe plurality of regions is shared by at least two of the multiplefilters while at least one other of the multiple filters separatelydetermines the region partition information to be used there by.

These and other features and advantages of the present principles may bereadily ascertained by one of ordinary skill in the pertinent art basedon the teachings herein. It is to be understood that the teachings ofthe present principles may be implemented in various forms of hardware,software, firmware, special purpose processors, or combinations thereof.

Most preferably, the teachings of the present principles are implementedas a combination of hardware and software. Moreover, the software may beimplemented as an application program tangibly embodied on a programstorage unit. The application program may be uploaded to, and executedby, a machine comprising any suitable architecture. Preferably, themachine is implemented on a computer platform having hardware such asone or more central processing units (“CPU”), a random access memory(“RAM”), and input/output (“I/O”) interfaces. The computer platform mayalso include an operating system and microinstruction code. The variousprocesses and functions described herein may be either part of themicroinstruction code or part of the application program, or anycombination thereof, which may be executed by a CPU. In addition,various other peripheral units may be connected to the computer platformsuch as an additional data storage unit and a printing unit.

It is to be further understood that, because some of the constituentsystem components and methods depicted in the accompanying drawings arepreferably implemented in software, the actual connections between thesystem components or the process function blocks may differ dependingupon the manner in which the present principles are programmed. Giventhe teachings herein, one of ordinary skill in the pertinent art will beable to contemplate these and similar implementations or configurationsof the present principles.

Although the illustrative embodiments have been described herein withreference to the accompanying drawings, it is to be understood that thepresent principles is not limited to those precise embodiments, and thatvarious changes and modifications may be effected therein by one ofordinary skill in the pertinent art without departing from the scope orspirit of the present principles. All such changes and modifications areintended to be included within the scope of the present principles asset forth in the appended claims.

The invention claimed is:
 1. An apparatus, comprising: a video encoderfor encoding image data for a plurality of regions in a picture, whereinsaid video encoder comprises multiple filters for filtering the imagedata based on region partition information for the plurality of regions,the region partition information defining segmentation of a picture intoa plurality of regions, and wherein the multiple filters being used withdifferent filtering parameters in each region, and wherein at least twoof the multiple filters use the same segmentation based on shared regionpartition information, and the region partition information isseparately determined for at least one other of the multiple filters,wherein the encoder uses signaling to allow a decoder to select theparticular set of region partition information and filter parametersused by the multiple filters during encoding.
 2. The apparatus of claim1, wherein the region partition information is combined with filterparameter adaptation based on at least one of coding information andpicture content.
 3. The apparatus of claim 1, wherein at least one ofthe region partition information and filter parameters for the multiplefilters are signaled using one or more high level syntax elements or oneor more region level syntax elements, or are inferred by a correspondingdecoder from at least one of previously coded regions, previously codedpictures, and previously coded video sequences, the picturecorresponding to a currently coded video sequence.
 4. The apparatus ofclaim 1, wherein the multiple filters comprise at least one of at leastone in-loop filter, at least one out-loop filter, at least onepre-processing filter, and at least one post-processing filter.
 5. Theapparatus of claim 1, wherein a partitioning of the picture into theplurality of regions, from which the region partitioning information isbased, is jointly optimized by the multiple filters.
 6. The apparatus ofclaim 1, wherein a partitioning of the picture into the plurality ofregions, from which the region partitioning information is based, isoptimized by one of the multiple filters, and is shared with other onesof the multiple filters.
 7. In a video encoder, a method, comprising:encoding image data for a plurality of regions in a picture, whereinsaid video encoder comprises multiple filters for filtering the imagedata based on region partition information for the plurality of regions,the region partition information defining segmentation of a picture intoa plurality of regions, and wherein the multiple filters being used withdifferent filtering parameters in each region, and wherein at least twoof the multiple filters use the same segmentation based on shared regionpartition information, and the region partition information isseparately determined for at least one other of the multiple filters,wherein the encoder uses signaling to allow a decoder to select theparticular set of region partition information and filter parametersused by the multiple filters during encoding.
 8. The method of claim 7,wherein the region partition information is combined with parameteradaptation based on at least one of coding information and picturecontent.
 9. The method of claim 7, wherein at least one of the regionpartition information and filter parameters for the multiple filters aresignaled using one or more high level syntax elements or one or moreregion level syntax elements, or are inferred by a corresponding decoderfrom at least one of previously coded regions, previously codedpictures, and previously coded video sequences, the picturecorresponding to a currently coded video sequence.
 10. The method ofclaim 7, wherein the multiple filters comprise at least one of at leastone in-loop filter, at least one out-loop filter, at least onepre-processing filter, and at least one post-processing filter.
 11. Themethod of claim 7, wherein a partitioning of the picture into theplurality of regions, from which the region partitioning information isbased, is jointly optimized by the multiple filters.
 12. The method ofclaim 7, wherein a partitioning of the picture into the plurality ofregions, from which the region partitioning information is based, isoptimized by one of the multiple filters, and is shared with other onesof the multiple filters.
 13. An apparatus, comprising: a video decoderfor decoding image data for a plurality of regions in a picture, whereinsaid video decoder comprises multiple filters for filtering the imagedata based on region partition information for the plurality of regions,the region partition information defining segmentation of a picture intoa plurality of regions, and wherein the multiple filters being used withdifferent filtering parameters in each region, and wherein at least twoof the multiple filters use the same segmentation based on shared regionpartition information, and the region partition information isseparately determined for at least one other of the multiple filters,wherein the decoder uses signaling to allow a decoder to select theparticular set of region partition information and filter parametersused by the multiple filters during decoding.
 14. The apparatus of claim13, wherein the region partition information is combined with parameteradaptation based on at least one of coding information and picturecontent.
 15. The apparatus of claim 13, wherein at least one of theregion partition information and filter parameters for the multiplefilters are determined from one or more high level syntax elements orone or more region level syntax elements, or are inferred from at leastone of previously coded regions, previously coded pictures, andpreviously coded video sequences, the picture corresponding to acurrently coded video sequence.
 16. The apparatus of claim 13, whereinthe multiple filters comprise at least one of at least one in-loopfilter, at least one out-loop filter, at least one pre-processingfilter, and at least one post-processing filter.
 17. In a video decoder,a method, comprising: decoding image data for a plurality of regions ina picture, wherein the image data is filtered by multiple filters basedon region partition information for the plurality of regions, the regionpartition information defining segmentation of a picture into aplurality of regions, and wherein the multiple filters being used with adifferent filter and different filtering parameters in each region, andwherein at least two of the multiple filters use the same segmentationbased on shared region partition information, and the region partitioninformation is separately determined for at least one other of themultiple filters, wherein the decoder uses signaling to allow a decoderto select the particular set of region partition information and filterparameters used by the multiple filters during decoding.
 18. The methodof claim 17, wherein the region partition information is combined withparameter adaptation based on at least one of coding information andpicture content.
 19. The method of claim 17, wherein at least one of theregion partition information and filter parameters for the multiplefilters are determined from one or more high level syntax elements orone or more region level syntax elements, or are inferred from at leastone of previously coded regions, previously coded pictures, andpreviously coded video sequences, the picture corresponding to acurrently coded video sequence.